A Northumbria Police spokesman said: "Inquiries are currently being carried out into the death.

"At this stage there is not believed to be any third-party involvement."

Scott lived a bizarre, lavish playboy lifestyle, funded by crime.

With a taste for Cuban cigars and champagne, which he claimed to consume daily, he became a career fraudster to fund his appetite for the high life, which included driving around in a yellow Ferrari.

He claimed to have international business interests and homes in Monte Carlo and Liechtenstein.

But in reality he had never worked in his life and instead managed to rack up £90,000 of credit card debt, while living on benefits.

And his fantasy unravelled in 2008 when he attempted to sell the £1.5m Shakespeare book, stolen from Durham University library in 1998.

He planned to use the proceeds to clear his debts and win the heart of a Cuban dancer he had become infatuated with while holidaying on the island.

But when he turned up at the renowned Folger Shakespeare Library in Washington DC, where he thought he could sell the damaged rare first folio, experts in the Bard’s works instantly recognised it as the one that had been stolen from Durham

An investigation was launched by Durham Constabulary and Scott was arrested at the Washington, Tyne and Wear, home he shared with his elderly mother in 2008.

During his trial at Newcastle Crown Court, Scott denied knowing that the collection of 36 plays, published seven years after Shakespeare’s death, was stolen and insisted he had found the 387-year-old work in Cuba.

But the jury found him guilty of handling stolen goods and removing stolen property from Britain, although he was cleared of stealing the book.

Judge Richard Lowden said the fact that the book had been defaced to hide its true identity was an act of cultural vandalism on a quintessentially English treasure.

The court heard how Scott had 25 previous convictions dating back to 1977, mainly for dishonesty.

In jailing him, Judge Lowden said: "You are to some extent a fantasist and have to some degree a personality disorder and you have been an alcoholic.

"It is clear that from the psychiatric report you are not suffering from any mental disorder.

"Your motivation was financial gain.

"You wanted to fund an extremely ludicrous playboy lifestyle in order to impress a woman you met in Cuba."

A Prison Service spokeswoman said: "HMP Northumberland prisoner Raymond Scott was pronounced dead at approximately 8.40am on Wednesday, March 14, after being found unconscious in his cell.

"As with all deaths in custody, the independent Prisons and Probation Ombudsman will conduct an investigation."